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Life Sciences Nov 2019Treatment of majority of eye diseases involve the use of eye drops or eye ointments, which have major drawbacks of needing frequent administration, lower bioavailability... (Review)
Review
Treatment of majority of eye diseases involve the use of eye drops or eye ointments, which have major drawbacks of needing frequent administration, lower bioavailability and inability to cross the various eye barriers. This necessitates the use of novel delivery systems. Microneedles (MNs) as an alternate novel delivery system facilitate drug delivery to various ocular diseases with promising approaches in healthcare. Advances in pharmaceutical technology have made MNs provide localized, effective, less invasive and targeted drug delivery in the eye. The purpose of this review is to provide an insight to efficacious therapeutic applications the MNs can bring in various ocular diseases. Out of which, glaucoma, age-related macular degeneration, uveitis, retinal vascular occlusion and retinitis pigmentosa are majorly discussed. Among the various types of MNs; solid coated, hollow and dissolving polymeric MNs are specifically focused for their applications in ocular diseases. In addition, MNs shows improvement in the visual acuity and decreases the progression of the different ocular diseases.
Topics: Administration, Ophthalmic; Animals; Drug Delivery Systems; Eye Diseases; Humans; Microinjections; Needles; Pharmaceutical Preparations
PubMed: 31606378
DOI: 10.1016/j.lfs.2019.116907 -
Methods in Molecular Biology (Clifton,... 2016Protein-tyrosine phosphatases (PTPs) are a large family of signal transduction regulators that have an essential role in normal development and physiology. Aberrant...
Protein-tyrosine phosphatases (PTPs) are a large family of signal transduction regulators that have an essential role in normal development and physiology. Aberrant activation or inactivation of PTPs is at the basis of many human diseases. The zebrafish, Danio rerio, is being used extensively to model major aspects of development and disease as well as the mechanism of regeneration of limbs and vital organs, and most classical PTPs have been identified in zebrafish. Zebrafish is an excellent model system for biomedical research because the genome is sequenced, zebrafish produce a large number of offspring, the eggs develop outside the mother and are transparent, facilitating intravital imaging, and transgenesis and (site-directed) mutagenesis are feasible. Together, these traits make zebrafish amenable for the analysis of gene and protein function. In this chapter we cover three manipulations of zebrafish embryos that we have used to study the effects of PTPs in development, regeneration, and biochemistry. Microinjection at the one-cell stage is at the basis of many zebrafish experiments and is described first. This is followed by a description for measuring regeneration of the embryonic caudal fin, a powerful and robust physiological assay. Finally, the considerable but manageable troubleshooting of several complications associated with preparing zebrafish embryos for immunoblotting is explained. Overall, this chapter provides detailed protocols for manipulating zebrafish embryo samples with a compilation of tips collected through extensive experience from the zebrafish research community.
Topics: Animals; Embryo, Nonmammalian; Equipment Design; Microinjections; Microscopy; Protein Tyrosine Phosphatases; Regeneration; Zebrafish
PubMed: 27514815
DOI: 10.1007/978-1-4939-3746-2_19 -
Methods in Molecular Biology (Clifton,... 2019Pronuclear microinjection remains the most widely used method for the germline modification of mice and other species. The method is conceptually quite simple and at...
Pronuclear microinjection remains the most widely used method for the germline modification of mice and other species. The method is conceptually quite simple and at least in rodents can produce transgenic offspring with relatively high efficiency. Here, we describe the various components of the production of transgenic mice including a detailed list of materials and equipment. We outline in detail the preparation of animals, the retrieval, culture and transfer of embryos, the preparation of DNA, and the microinjection process. We have added a substantial collection of notes with helpful suggestions that reflect the many years of experience we have using this technology and our continuing efforts to improve animal welfare and the efficiency of producing transgenics.
Topics: Animals; Cell Nucleus; DNA; Embryo Culture Techniques; Embryo Transfer; Female; Gene Transfer Techniques; Male; Mice; Mice, Transgenic; Microinjections
PubMed: 30353506
DOI: 10.1007/978-1-4939-8831-0_2 -
Mikrochimica Acta Jun 2024Microneedles, the miniaturized needles, which can pierce the skin with minimal invasiveness open up new possibilities for constructing personalized Point-of-Care (POC)... (Review)
Review
Microneedles, the miniaturized needles, which can pierce the skin with minimal invasiveness open up new possibilities for constructing personalized Point-of-Care (POC) diagnostic platforms. Recent advances in microneedle-based POC diagnostic systems, especially their successful implementation with wearable technologies, enable biochemical detection and physiological recordings in a user-friendly manner. This review presents an overview of the current advances in microneedle-based sensor devices, with emphasis on the biological basis of transdermal sensing, fabrication, and application of different types of microneedles, and a summary of microneedle devices based on various sensing strategies. It concludes with the challenges and future prospects of this swiftly growing field. The aim is to present a critical and thorough analysis of the state-of-the-art development of transdermal diagnostics and sensing devices based on microneedles, and to bridge the gap between microneedle technology and pragmatic applications.
Topics: Needles; Humans; Microinjections; Skin; Point-of-Care Systems; Animals; Biosensing Techniques; Wearable Electronic Devices
PubMed: 38898359
DOI: 10.1007/s00604-024-06458-2 -
Journal of Plant Physiology Jan 2020The microinjection of fluorescent probes into live cells is an essential component in the toolbox of modern cell biology. Microinjection techniques include the...
The microinjection of fluorescent probes into live cells is an essential component in the toolbox of modern cell biology. Microinjection techniques include the penetration of the plasma membrane and, if present, the cell wall with micropipettes, and the application of pressure or electrical currents to drive the micropipette contents into the cell. These procedures interfere with cellular functions and therefore may induce artifacts. We designed the diffusive injection micropipette (DIMP) that avoids most of the possible artifacts due to the drastically reduced volume of its fluid contents and the utilization of diffusion for cargo delivery into the target cell. DIMPs were successfully tested in plant, fungal, and animal cells. Using the continuity of cytoplasmic dynamics over ten minutes after impalement of Nicotiana trichome cells as a criterion for non-invasiveness, we found DIMPs significantly less disruptive than conventional pressure microinjection. The design of DIMPs abolishes major sources of artifacts that cannot be avoided by other microinjection techniques. Moreover, DIMPs are inexpensive, easy to produce, and can be applied without specific equipment other than a micromanipulator. With these features, DIMPs may become the tool of choice for studies that require the least invasive delivery possible of materials into live cells.
Topics: Aspergillus niger; Cell Line; Fluorescent Dyes; Humans; Microinjections; Nicotiana
PubMed: 31765880
DOI: 10.1016/j.jplph.2019.153060 -
The Review of Scientific Instruments Jan 2022Unlike cells or embryos, zebrafish have a complex physiological structure, which poses challenges to posture recognition and adjustment during microinjection....
Unlike cells or embryos, zebrafish have a complex physiological structure, which poses challenges to posture recognition and adjustment during microinjection. Furthermore, zebrafish surface pigments exhibit strong interference with visual servo-based injection control, thus, affecting the success of microinjection and the subsequent survival rate. To address these challenges, we developed an automated microinjection system for the zebrafish heart that has advantages of high accuracy and success rate and avoids biological sample contamination. A convolutional neural networks (CNN) deep learning model is employed to determine the body axis posture. To solve the problems of blocked needle and abnormal tip positioning induced by zebrafish surface pigment during the injection process, an adaptive robust Kalman filter is proposed to suppress the abnormal values of visual feedback. Experimental results show that the success rate of body axis recognition based on the employed deep learning model exceeds 95%, and the proposed adaptive Kalman filter effectively suppresses the visual outliers, satisfying the requirements of high-precision injection for the zebrafish heart.
Topics: Animals; Heart; Larva; Microinjections; Posture; Zebrafish
PubMed: 35104951
DOI: 10.1063/5.0064563 -
Biopolymers May 2024Microneedles are a transdermal drug delivery system in which the needle punctures the epithelium to deliver the drug directly to deep tissues, thus avoiding the... (Review)
Review
Microneedles are a transdermal drug delivery system in which the needle punctures the epithelium to deliver the drug directly to deep tissues, thus avoiding the influence of the first-pass effect of the gastrointestinal tract and minimizing the likelihood of pain induction. Hydrogel microneedles are microneedles prepared from hydrogels that have good biocompatibility, controllable mechanical properties, and controllable drug release and can be modified to achieve environmental control of drug release in vivo. The large epithelial tissue in the oral cavity is an ideal site for drug delivery via microneedles. Hydrogel microneedles can overcome mucosal hindrances to delivering drugs to deep tissues; this prevents humidity and a highly dynamic environment in the oral cavity from influencing the efficacy of the drugs and enables them to obtain better therapeutic effects. This article analyzes the materials and advantages of common hydrogel microneedles and reviews the application of hydrogel microneedles in the oral cavity.
Topics: Needles; Hydrogels; Mouth; Humans; Drug Delivery Systems; Animals; Microinjections
PubMed: 38506560
DOI: 10.1002/bip.23573 -
Methods in Molecular Biology (Clifton,... 2020The ability to delete the function of an endogenous gene in the mouse was made possible by the development of embryonic stem (ES) cells, pluripotent cells that retain...
The ability to delete the function of an endogenous gene in the mouse was made possible by the development of embryonic stem (ES) cells, pluripotent cells that retain the ability to develop into all tissues of a developing embryo. The ability to genetically modify these cells followed, allowing targeted mutation of ES cells in vitro and the deletion of specific gene function. However, regardless of the simplicity or complexity of the genetic modification, all ES cells require injection into host embryos to establish pregnancies and result in chimeric mice. Blastocysts are commonly used as the host embryos for this purpose, as it is relatively easy to inject cells into the blastocoel cavity of the developing embryo. This chapter describes the procedure for injection of ES cells into blastocyst stage embryos for the generation of knockout mice.
Topics: Animals; Blastocyst; Chimera; Embryo Transfer; Embryonic Stem Cells; Female; Mice; Mice, Knockout; Microinjections; Pregnancy
PubMed: 31512208
DOI: 10.1007/978-1-4939-9837-1_6 -
Pharmaceutical Development and... Nov 2021The use of 3D printing (3DP) technology, which has been continuously evolving since the 1980s, has recently become common in healthcare services. The introduction of 3DP... (Review)
Review
The use of 3D printing (3DP) technology, which has been continuously evolving since the 1980s, has recently become common in healthcare services. The introduction of 3DP into the pharmaceutical industry particularly aims at the development of patient-centered dosage forms based on structure design. It is still a new research direction with potential to create the targeted release of drug delivery systems in freeform geometries. Although the use of 3DP technology for solid oral dosage forms is more preferable, studies on transdermal applications of the technology are also increasing. Microneedle sequences are one of the transdermal drug delivery (TDD) methods which are used to bypass the minimally invasive with novel delivery methods for small molecule drugs and vaccines. Microneedle arrays have advantages over many traditional methods. It is attractive with features such as ease of application, controlled release of active substances and patient compliance. Recently, 3D printers have been used for the production of microneedle patches. After giving a brief overview of 3DP technology, this article includes the materials necessary for the preparation of microneedles and microneedle patches specifically for penetration enhancement, preparation methods, quality parameters, and their application to TDD. In addition, the applicability of 3D microneedles in the pharmaceutical industry has been evaluated.
Topics: Administration, Cutaneous; Animals; Drug Delivery Systems; Equipment Design; Humans; Microinjections; Needles; Pharmaceutical Preparations; Printing, Three-Dimensional; Skin Absorption
PubMed: 34369288
DOI: 10.1080/10837450.2021.1965163 -
Small (Weinheim An Der Bergstrasse,... Jul 2023Microneedles have recently emerged as a powerful tool for minimally invasive drug delivery and body fluid sampling. To date, high-resolution fabrication of microneedle...
Microneedles have recently emerged as a powerful tool for minimally invasive drug delivery and body fluid sampling. To date, high-resolution fabrication of microneedle arrays (MNAs) is mostly achieved by the utilization of sophisticated facilities and expertise. Particularly, hollow microneedles have usually been manufactured in cleanrooms out of silicon, resin, or metallic materials. Such strategies do not support the fabrication of microneedles from biocompatible/biodegradable materials and limit the capability of multimodal drug delivery for the controlled release of different therapeutics through a combination of injection and sustained diffusion. This study implements low-cost 3D printers to fabricate relatively large needle arrays, followed by repeatable shrink-molding of hydrogels to form high-resolution molds for solid and hollow MNAs with controllable sizes. The developed strategy further enables modulating surface topography of MNAs to tailor their surface area and instantaneous wettability for controllable drug delivery and body fluid sampling. Hybrid gelatin methacryloyl (GelMA)/polyethylene glycol diacrylate (PEGDA) MNAs are fabricated using the developed strategy that can easily penetrate the skin and enable multimodal drug delivery. The proposed method holds promise for affordable, controllable, and scalable fabrication of MNAs by researchers and clinicians for controlled spatiotemporal administration of therapeutics and sample collection.
Topics: Administration, Cutaneous; Microinjections; Skin; Drug Delivery Systems; Biocompatible Materials
PubMed: 37026428
DOI: 10.1002/smll.202207131