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Abstract
In vivo imaging, which enables us to peer deeply within living subjects, is producing tremendous opportunities both for clinical diagnostics and as a research tool. Contrast material is often required to clearly visualize the functional architecture of physiological structures. Recent advances in nanomaterials are becoming pivotal to generate the high-resolution, high-contrast images needed for accurate, precision diagnostics. Nanomaterials are playing major roles in imaging by delivering large imaging payloads, yielding improved sensitivity, multiplexing capacity, and modularity of design. Indeed, for several imaging modalities, nanomaterials are now not simply ancillary contrast entities, but are instead the original and sole source of image signal that make possible the modality's existence. We address the physicochemical makeup/design of nanomaterials through the lens of the physical properties that produce contrast signal for the cognate imaging modality-we stratify nanomaterials on the basis of their (i) magnetic, (ii) optical, (iii) acoustic, and/or (iv) nuclear properties. We evaluate them for their ability to provide relevant information under preclinical and clinical circumstances, their in vivo safety profiles (which are being incorporated into their chemical design), their modularity in being fused to create multimodal nanomaterials (spanning multiple different physical imaging modalities and therapeutic/theranostic capabilities), their key properties, and critically their likelihood to be clinically translated.
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Affiliation(s)
- Bryan Ronain Smith
- Stanford University , 3155 Porter Drive, #1214, Palo Alto, California 94304-5483, United States
| | - Sanjiv Sam Gambhir
- The James H. Clark Center , 318 Campus Drive, First Floor, E-150A, Stanford, California 94305-5427, United States
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Kaspar RL, Hickerson RP, González-González E, Flores MA, Speaker TP, Rogers FA, Milstone LM, Contag CH. Imaging Functional Nucleic Acid Delivery to Skin. Methods Mol Biol 2015; 1372:1-24. [PMID: 26530911 DOI: 10.1007/978-1-4939-3148-4_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Monogenic skin diseases arise from well-defined single gene mutations, and in some cases a single point mutation. As the target cells are superficial, these diseases are ideally suited for treatment by nucleic acid-based therapies as well as monitoring through a variety of noninvasive imaging technologies. Despite the accessibility of the skin, there remain formidable barriers for functional delivery of nucleic acids to the target cells within the dermis and epidermis. These barriers include the stratum corneum and the layered structure of the skin, as well as more locally, the cellular, endosomal and nuclear membranes. A wide range of technologies for traversing these barriers has been described and moderate success has been reported for several approaches. The lessons learned from these studies include the need for combinations of approaches to facilitate nucleic acid delivery across these skin barriers and then functional delivery across the cellular and nuclear membranes for expression (e.g., reporter genes, DNA oligonucleotides or shRNA) or into the cytoplasm for regulation (e.g., siRNA, miRNA, antisense oligos). The tools for topical delivery that have been evaluated include chemical, physical and electrical methods, and the development and testing of each of these approaches has been greatly enabled by imaging tools. These techniques allow delivery and real time monitoring of reporter genes, therapeutic nucleic acids and also triplex nucleic acids for gene editing. Optical imaging is comprised of a number of modalities based on properties of light-tissue interaction (e.g., scattering, autofluorescence, and reflectance), the interaction of light with specific molecules (e.g., absorbtion, fluorescence), or enzymatic reactions that produce light (bioluminescence). Optical imaging technologies operate over a range of scales from macroscopic to microscopic and if necessary, nanoscopic, and thus can be used to assess nucleic acid delivery to organs, regions, cells and even subcellular structures. Here we describe the animal models, reporter genes, imaging approaches and general strategies for delivery of nucleic acids to cells in the skin for local expression (e.g., plasmid DNA) or gene silencing (e.g., siRNA) with the intent of developing nucleic acid-based therapies to treat diseases of the skin.
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Affiliation(s)
- Roger L Kaspar
- TransDerm Inc., 2161 Delaware Ave, Santa Cruz, CA, 95060, USA.
| | - Robyn P Hickerson
- Centre for Dermatology and Genetic Medicine, University of Dundee, Dundee, UK
| | | | - Manuel A Flores
- TransDerm Inc., 2161 Delaware Ave, Santa Cruz, CA, 95060, USA
| | - Tycho P Speaker
- TransDerm Inc., 2161 Delaware Ave, Santa Cruz, CA, 95060, USA
| | - Faye A Rogers
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - Leonard M Milstone
- Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA
| | - Christopher H Contag
- Molecular Imaging Program at Stanford (MIPS), E150 Clark Center, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA, 94305, USA. .,Department of Pediatrics, E150 Clark Center, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA, 94305, USA. .,Department of Radiology, E150 Clark Center, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA, 94305, USA. .,Microbiology and Immunology, E150 Clark Center, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA, 94305, USA.
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Shi B, Abrams M. Technologies for investigating the physiological barriers to efficient lipid nanoparticle-siRNA delivery. J Histochem Cytochem 2013; 61:407-20. [PMID: 23504369 PMCID: PMC3715328 DOI: 10.1369/0022155413484152] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/20/2013] [Indexed: 11/22/2022] Open
Abstract
Small interfering RNA (siRNA) therapeutics have advanced from bench to clinical trials in recent years, along with new tools developed to enable detection of siRNA delivered at the organ, cell, and subcellular levels. Preclinical models of siRNA delivery have benefitted from methodologies such as stem-loop quantitative polymerase chain reaction, histological in situ immunofluorescent staining, endosomal escape assay, and RNA-induced silencing complex loading assay. These technologies have accelerated the detection and optimization of siRNA platforms to overcome the challenges associated with delivering therapeutic oligonucleotides to the cytosol of specific target cells. This review focuses on the methodologies and their application in the biodistribution of siRNA delivered by lipid nanoparticles.
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Affiliation(s)
- Bin Shi
- Department of RNA Therapeutics, Merck Research Laboratories, Merck & Co., Inc., West Point, Pennsylvania, USA.
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Zhu H, Isikman SO, Mudanyali O, Greenbaum A, Ozcan A. Optical imaging techniques for point-of-care diagnostics. LAB ON A CHIP 2013; 13:51-67. [PMID: 23044793 PMCID: PMC3510351 DOI: 10.1039/c2lc40864c] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Improving access to effective and affordable healthcare has long been a global endeavor. In this quest, the development of cost-effective and easy-to-use medical testing equipment that enables rapid and accurate diagnosis is essential to reduce the time and costs associated with healthcare services. To this end, point-of-care (POC) diagnostics plays a crucial role in healthcare delivery in both developed and developing countries by bringing medical testing to patients, or to sites near patients. As the diagnosis of a wide range of diseases, including various types of cancers and many endemics, relies on optical techniques, numerous compact and cost-effective optical imaging platforms have been developed in recent years for use at the POC. Here, we review the state-of-the-art optical imaging techniques that can have a significant impact on global health by facilitating effective and affordable POC diagnostics.
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Affiliation(s)
- Hongying Zhu
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Serhan O. Isikman
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Onur Mudanyali
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Alon Greenbaum
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Aydogan Ozcan
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
- Bioengineering Department, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute (CNSI), University of California, Los Angeles, CA 90095, USA
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González-González E, Kim YC, Speaker TJ, Hickerson RP, Spitler R, Birchall JC, Lara MF, Hu RH, Liang Y, Kirkiles-Smith N, Prausnitz MR, Milstone LM, Contag CH, Kaspar RL. Visualization of plasmid delivery to keratinocytes in mouse and human epidermis. Sci Rep 2011; 1:158. [PMID: 22355673 PMCID: PMC3240989 DOI: 10.1038/srep00158] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 10/26/2011] [Indexed: 02/06/2023] Open
Abstract
The accessibility of skin makes it an ideal target organ for nucleic acid-based therapeutics; however, effective patient-friendly delivery remains a major obstacle to clinical utility. A variety of limited and inefficient methods of delivering nucleic acids to keratinocytes have been demonstrated; further advances will require well-characterized reagents, rapid noninvasive assays of delivery, and well-developed skin model systems. Using intravital fluorescence and bioluminescence imaging and a standard set of reporter plasmids we demonstrate transfection of cells in mouse and human xenograft skin using intradermal injection and two microneedle array delivery systems. Reporter gene expression could be detected in individual keratinocytes, in real-time, in both mouse skin as well as human skin xenografts. These studies revealed that non-invasive intravital imaging can be used as a guide for developing gene delivery tools, establishing a benchmark for comparative testing of nucleic acid skin delivery technologies.
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Affiliation(s)
- Emilio González-González
- Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford, CA 94305, USA
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In vivo imaging of human and mouse skin with a handheld dual-axis confocal fluorescence microscope. J Invest Dermatol 2010; 131:1061-6. [PMID: 21191407 DOI: 10.1038/jid.2010.401] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Advancing molecular therapies for the treatment of skin diseases will require the development of new tools that can reveal spatiotemporal changes in the microanatomy of the skin and associate these changes with the presence of the therapeutic agent. For this purpose, we evaluated a handheld dual-axis confocal (DAC) microscope that is capable of in vivo fluorescence imaging of skin, using both mouse models and human skin. Individual keratinocytes in the epidermis were observed in three-dimensional image stacks after topical administration of near-infrared (NIR) dyes as contrast agents. This suggested that the DAC microscope may have utility in assessing the clinical effects of a small interfering RNA (siRNA)-based therapeutic (TD101) that targets the causative mutation in pachyonychia congenita (PC) patients. The data indicated that (1) formulated indocyanine green (ICG) readily penetrated hyperkeratotic PC skin and normal callused regions compared with nonaffected areas, and (2) TD101-treated PC skin revealed changes in tissue morphology, consistent with reversion to nonaffected skin compared with vehicle-treated skin. In addition, siRNA was conjugated to NIR dye and shown to penetrate through the stratum corneum barrier when topically applied to mouse skin. These results suggest that in vivo confocal microscopy may provide an informative clinical end point to evaluate the efficacy of experimental molecular therapeutics.
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