Phys Sci Res Assoc, Chemistry
Postdoctoral Fellow, Georgia Institute of Technology, Chemical and Biomolecular Engineering (2019)
PhD, Case Western Reserve University, Polymer Science and Engineering (2016)
MSc, Amirkabir University of Technology, Chemical Engineering (2008)
BSc, Sahand University of Technology, Chemical Engineering (2004)
Eric Baer, Gary E. Wnek, Mohammad Mofidfar, Jia Wang. "Polymer Fiber Scaffolds and Uses Thereof", US Patent # 10751293 B2, Aug 25, 2020
- On-demand electrochemically controlled compound release from an ultrasonically powered implant RSC ADVANCES 2022; 12 (36): 23337-23345
Capturing Reactive Carbanions by Microdroplets.
Journal of the American Chemical Society
Carbanions appear in many organic or biological reactions as fleeting intermediates, prohibiting direct observation or spectroscopic measurement. An aqueous environment is known to rapidly annihilate a carbanion species, reducing its lifetime to as short as picoseconds. We report that aqueous microdroplets can capture and stabilize reactive carbanion intermediates isolated from four classic organic reactions, aldol and Knoevenagel condensations, alkyne alkylation, and the Reimer-Tiemann reaction, enabling the detection of their carbanion intermediates by desorption electrospray ionization mass spectrometry. This is accomplished in real time of the reaction, allowing new insights into reaction mechanisms to be obtained. The efficacy of microdroplets in capturing such elusive species was examined by varying the solvent and the microdroplet negative charge density. We observed that microdroplets composed of water-methanol outperform other solvents, such as pure water, in capturing carbanions, which is in contrast to the earlier report that presented the highest performance of pure water microdroplets in capturing carbocations. We offer some mechanistic insights to explain the discriminatory behavior of these two oppositely charged species in microdroplets.
View details for DOI 10.1021/jacs.2c01577
View details for PubMedID 35452233
Sprayed Water Microdroplets Are Able to Generate Hydrogen Peroxide Spontaneously.
Journal of the American Chemical Society
Ultrapure N2 gas was bubbled through water, and the humidified output containing undetectable concentrations of ozone filled a closed chamber in which 18 MOmega-cm water was sprayed through a silica capillary to form microdroplets. Analysis of the collected microdroplets by NMR spectroscopy showed the presence of hydrogen peroxide at a concentration level ranging from 0.3 to 1.5 muM depending on the flow conditions. This was confirmed using a spectrofluorometric assay. We suggest that this finding establishes that when sprayed to form microdroplets, water has the ability to produce hydrogen peroxide by itself. When the N2 gas is replaced by compressed air or O2 gas, the concentration of hydrogen peroxide is found to increase, indicating that gas-surface interactions with O2 in aqueous microdroplets promote the formation of hydrogen peroxide.
View details for DOI 10.1021/jacs.2c02890
View details for PubMedID 35451822
Advances in microfabrication technologies in tissue engineering and regenerative medicine.
BACKGROUND: Tissue engineering provides various strategies to fabricate an appropriate microenvironment to support the repair and regeneration of lost or damaged tissues. In this matter, several technologies have been implemented to construct close-to-native three-dimensional structures at numerous physiological scales, which are essential to confer the functional characteristics of living tissues.METHODS: In this article, we review a variety of microfabrication technologies that are currently utilized for several tissue engineering applications, such as soft lithography, microneedles, templated and self-assembly of microstructures, microfluidics, fiber spinning, and bioprinting.RESULTS: These technologies have considerably helped us to precisely manipulate cells or cellular constructs for the fabrication of biomimetic tissues and organs. Although currently available tissues still lack some crucial functionalities, including vascular networks, innervation, and lymphatic system, microfabrication strategies are being proposed to overcome these issues. Moreover, the microfabrication techniques that have progressed to the preclinical stage are also discussed.CONCLUSIONS: This article aims to highlight the advantages and drawbacks of each technique and areas of further research for a more comprehensive and evolving understanding of microfabrication techniques in terms of tissue engineering and regenerative medicine applications.
View details for DOI 10.1111/aor.14232
View details for PubMedID 35349178
Drug delivery to the anterior segment of the eye: a review of current and future treatment strategies.
International journal of pharmaceutics
Research in the development of ophthalmic drug formulations and innovative technologies over the past few decades has been directed at improving the penetration of medications delivered to the eye. Currently, approximately 90% of all ophthalmic drug formulations (e.g. liposomes, micelles) are applied as eye drops. The major challenge of topical eye drops is low bioavailability, need for frequent instillation due to the short half-life, poor drug solubility, and potential side effects. Recent research has been focused on improving topical drug delivery devices by increasing ocular residence time, overcoming physiological and anatomical barriers, and developing medical devices and drug formulations to increase the duration of action of the active drugs. Researchers have developed innovative technologies and formulations ranging from sub-micron to macroscopic size such as prodrugs, enhancers, mucus-penetrating particles (MPPs), therapeutic contact lenses, and collagen corneal shields. Another approach towards the development of effective topical drug delivery is embedding therapeutic formulations in microdevices designed for sustained release of the active drugs. The goal is to optimize the delivery of ophthalmic medications by achieving high drug concentration with prolonged duration of action that is convenient for patients to administer.
View details for DOI 10.1016/j.ijpharm.2021.120924
View details for PubMedID 34324989
Introducing Nafion for In Situ Desalting and Biofluid Profiling in Spray Mass Spectrometry.
Frontiers in chemistry
2021; 9: 807244
We introduce Nafion into the ambient ionization technique of spray mass spectrometry to serve for in situ desalting and direct analysis of biological fluids. Nafion was coated onto the surface of the triangular spray tip as the cation exchange material. Because the sulfonic group from the Nafion membrane effectively exchanges their carried protons with inorganic salt ions (e.g., Na+ and K+), the analyte's ionization efficiency can be significantly enhanced by reducing ion suppression. The desalting efficiency can reach 90% and the maximum tolerance of the absolute salt amount reaches 100 μmol. The mass spectral profile can also be simplified by removing the multiple adducted ion types from small-molecule drugs and metabolites ([M + Na]+ and [M + K]+), or multiply charged ions formed by proteins ([M + nNa]n+ and [M + nK]n+). Thus, the Nafion coating makes less ambiguous data interpretation collected from spray mass spectrometry for qualitative profiling or quantitative measurement of a target analyte.
View details for DOI 10.3389/fchem.2021.807244
View details for PubMedID 35145954
View details for PubMedCentralID PMC8821663
A Wireless Implantable Potentiostat for Programmable Electrochemical Drug Delivery
IEEE Biomedical Circuits and Systems (BIOCAS)
View details for DOI 10.1109/BioCAS49922.2021.9644991
Distinguishing between Isobaric Ions Using Microdroplet Hydrogen–Deuterium Exchange Mass Spectrometry
View details for DOI 10.3390/metabo11110728
Extrusion and Microfluidic-Based Bioprinting to Fabricate Biomimetic Tissues and Organs
ADVANCED MATERIALS TECHNOLOGIES
2020; 5 (8)
Next generation engineered tissue constructs with complex and ordered architectures aim to better mimic the native tissue structures, largely due to advances in three-dimensional (3D) bioprinting techniques. Extrusion bioprinting has drawn tremendous attention due to its widespread availability, cost-effectiveness, simplicity, and its facile and rapid processing. However, poor printing resolution and low speed have limited its fidelity and clinical implementation. To circumvent the downsides associated with extrusion printing, microfluidic technologies are increasingly being implemented in 3D bioprinting for engineering living constructs. These technologies enable biofabrication of heterogeneous biomimetic structures made of different types of cells, biomaterials, and biomolecules. Microfluiding bioprinting technology enables highly controlled fabrication of 3D constructs in high resolutions and it has been shown to be useful for building tubular structures and vascularized constructs, which may promote the survival and integration of implanted engineered tissues. Although this field is currently in its early development and the number of bioprinted implants is limited, it is envisioned that it will have a major impact on the production of customized clinical-grade tissue constructs. Further studies are, however, needed to fully demonstrate the effectiveness of the technology in the lab and its translation to the clinic.
View details for DOI 10.1002/admt.201901044
View details for Web of Science ID 000535259900001
View details for PubMedID 33072855
View details for PubMedCentralID PMC7567134
Micro and nanoscale technologies in oral drug delivery
ADVANCED DRUG DELIVERY REVIEWS
2020; 157: 37-62
Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.
View details for DOI 10.1016/j.addr.2020.07.012
View details for Web of Science ID 000600556900002
View details for PubMedID 32707147
View details for PubMedCentralID PMC7374157
Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers
2019; 10 (12)
: Bacterial and fungal pathogens have caused serious problems to the human health. This is particularly true for untreatable infectious diseases and clinical situations where there is no reliable treatment for infected patients. To increase the antimicrobial activity of materials, we introduce silver nanoparticle (NP) patches in which the NPs are incorporated to the surface of smooth and uniform poly(acrylic acid) (PAA) nanofibers. The PAA nanofibers were thermally crosslinked with ethylene glycol via heat treatment through a mild method. The characterization of the resulting PAA-silver NP patches was done using scanning electron microscopy (SEM), UV spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To demonstrate the antimicrobial activity of PAA, we incorporated the patches containing the silver NPs into strains of fungi such as Candida albicans (C. albican) and bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA). The PAA-silver fibers achieved zones of inhibition against C. albicans and MRSA indicating their antimicrobial activity against both fungi and bacteria. We conclude that silver NP patches exhibited multiple inhibitory actions for the interruption and blockage of activity fungal and bacterial strains, which has the potential as an antimicrobial agent in infectious diseases. Moreover, the proposed material has the potential to be used in antimicrobial textile fabrics, food packaging films, and wound dressings.
View details for DOI 10.3390/mi10120829
View details for Web of Science ID 000507337900017
View details for PubMedID 31795271
View details for PubMedCentralID PMC6953080
Pharmaceutical jewelry: Earring patch for transdermal delivery of contraceptive hormone
JOURNAL OF CONTROLLED RELEASE
2019; 301: 140-145
Lack of adherence to medication dosing schedules is a significant cause of morbidity and mortality with large associated financial costs. This is especially true for contraceptive hormones, which provide almost perfect prevention of pregnancy when used correctly, but have significant failure rates in typical use, due largely to poor adherence. To increase medication acceptability and adherence, we introduce pharmaceutical jewelry, in which a transdermal patch is incorporated into jewelry worn on skin. To demonstrate the approach, we incorporated transdermal patches containing the contraceptive hormone levonorgestrel (LNG) into an earring, a ring, a necklace, and a wrist watch. Transdermal delivery of LNG from earring patches across porcine skin ex vivo achieved a steady state flux of 1.7 μg/cm2·h. Pharmacokinetic analysis in hairless rats yielded LNG delivery rates that maintained serum LNG levels near 1500 pg/ml throughout the 1-week patch application period, which is well above the human contraceptive threshold concentration of 200 pg/ml. When patches were applied cyclically for 16 h on and 8 h off to simulate earring removal at night, serum LNG concentrations dipped during off periods, but remained well above the human contraceptive threshold. Earring patches were well tolerated by the rats. We conclude that pharmaceutical jewelry can provide a novel method of drug delivery, especially for contraceptive hormones, that has the potential to improve acceptability and increase medication adherence.
View details for DOI 10.1016/j.jconrel.2019.03.011
View details for Web of Science ID 000466361500011
View details for PubMedID 30876952
Electrospun Transdermal Patch for Contraceptive Hormone Delivery
CURRENT DRUG DELIVERY
2019; 16 (6): 577-583
A transdermal patch for delivery of Levonorgestrel (LNG) can be used for long-acting contraception.In this study, we designed and characterized a patch made of nonwoven electrospun microfibers comprised of Polycaprolactone (PCL) encapsulating LNG for slow release in a mineral oil matrix.Scanning electron microscopy showed uniform, randomly oriented PCL fibers with large interconnected voids filled with mineral oil. Thermogravimetric analysis indicated that LNG loaded into PCL fibers had thermal stability up to ~200°C. Differential Scanning Calorimetry suggested that LNG was dispersed in the electrospun fibers without interaction between the LNG and PCL, and without formation of drug crystals. Fourier Transform Infrared spectroscopy and X-ray diffraction results further supported the conclusion that there was no chemical drug-polymer interaction in LNGloaded fibers. Effective in vitro flux (i) from patches into mineral oil was 1.9 µgcm-2h-1, (ii) from mineral oil across porcine skin was 4.6 µgcm-2h-1 and (iii) from patches across porcine skin was 1.7 μgcm- 2h-1, indicating that transdermal delivery rate was controlled by a combination of the patch and the skin.The LNG-loaded patches demonstrated steady delivery of LNG across skin for up to 5 days in vitro. With additional development, LNG-loaded electrospun PCL patches could be used for long-acting contraception.
View details for DOI 10.2174/1567201816666190308112010
View details for Web of Science ID 000483386900009
View details for PubMedID 30848203
Polymeric Nanofiber/Antifungal Formulations Using a Novel Co-extrusion Approach
2017; 18 (6): 1917-1924
We report the successful implementation of a novel melt co-extrusion process to fabricate ca. 1 μm diameter fibers of poly(caprolactone) (PCL) containing the antifungal compound clotrimazole in concentrations between 4 and 8 wt%. The process involves co-extrusion of a clotrimazole-loaded PCL along with poly(ethylene oxide) (PEO) as a co-feed, with subsequent removal of PEO to isolate PCL-clotrimazole fibers. In vitro tests of the clotrimazole-containing fibers against the fungus Aspergillus fumigatus, Candida albicans, and Trichophyton mentagrophytes strains demonstrated good antifungal activity which was maintained for more than 3 weeks. An in vivo study using a mouse model showed the lowest tissue fungal burden for PCL-clotrimazole when compared to a PCL-only patch and untreated controls. Comparative studies were conducted with clotrimazole-containing PCL fibers fabricated by electrospinning. Our data showed that the co-extruded, clotrimazole-containing fibers maintain activity for longer times vs. electrospun samples. This, coupled with the much higher throughput of the co-extrusion process vs. electrospinning, renders this new approach very attractive for the fabrication of drug-releasing polymer fibers.
View details for DOI 10.1208/s12249-016-0664-2
View details for Web of Science ID 000406652000003
View details for PubMedID 27858252