Injectable PLGA-Coated Ropivacaine Produces A Long-Lasting Analgesic Effect on Incisional Pain and Neuropathic Pain.

The management of persistent postsurgical pain and neuropathic pain remains a challenge in the clinic. Local anesthetics have been widely used as simple and effective treatment for these 2 disorders, but the duration of their analgesic effect is short. We here reported a new poly lactic-co-glycolic acid (PLGA)-coated ropivacaine that was continuously released in vitro for at least 6 days. Perisciatic nerve injection of the PLGA-coated ropivacaine attenuated paw incision-induced mechanical allodynia and heat hyperalgesia during the incisional pain period, and spared nerve injury-induced mechanical and cold allodynia for at least 7 days postinjection. This effect was dose-dependent. Perisciatic nerve injection of the PLGA-coated ropivacaine did not produce detectable inflammation, tissue irritation, or damage in the sciatic nerve and surrounding muscles at the injected site, dorsal root ganglion, spinal cord, or brain cortex, although the scores for grasping reflex were mildly and transiently reduced in the higher dosage-treated groups. PERSPECTIVE: Given that PLGA is an FDA-approved medical material, and that ropivacaine is used currently in clinical practice, the injectable PLGA-coated ropivacaine represents a new and highly promising avenue in the management of postsurgical pain and neuropathic pain.

Effect of surface bonding of FePC with electrospun carbon nanofiber on electrocatalytic performance for aprotic Li-O2 batteries.

The bifunctional catalysts assist the complete reversible cycle of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with low polarization of a lithium-oxygen (Li-O2) battery were known to be critical cathode components. In this work, electrospun nitrogen-doped carbon nanofibers (N-CNFs) were prepared to use as supports to anchor iron phthalocyanine (FePc) bifunctional catalyst for oxygen (O2) electrode in Li-O2 batteries. By using FePc and N-CNFs, two different bonding composites were fabricated via diazonium reaction by refluxing and physical mixing methods which were resulting into covalent linkage via pyridine (Py) (denoted as FePc/Py/N-CNFs) and noncovalent interaction via π-π stacking (denoted as FePc/N-CNFs). The systematic characterizations confirmed that the spun carbon nanofibers were functionalized by pyridine and the anchored FePc molecule donated the axial ligand for the iron (Fe) center in the FePc/Py/N-CNFs composite. The FePc were embedded in the N-CNFs composites combining the electrocatalytic activity of the FePc with ORR/OER processes and N-CNFs with a three-dimensional (3D) interconnected porous network structure through a connecting link of one-dimensional (1D) porous and N-doping carbon nanofiber which exhibited a high performance when acting as the cathode in Li-O2 batteries. However, the FePc/Py/N-CNFs composite showed the higher catalytic activity and prominent structural stability due to the FePc being strongly interlinked with the N-CNFs through the Py connection, which could avoid the deformation and agglomeration of FePC molecules during cycling and thus possessed the high electrochemical performance of the composite. This study demonstrated the unique design of FePc/Py/N-CNFs composite structure in this work would be found as a promising O2 electrode material with enhanced electrochemical performance in rechargeable Li-O2 batteries.

Injectable Citrate-Based Hydrogel as an Angiogenic Biomaterial Improves Cardiac Repair after Myocardial Infarction.

Implanted medical biomaterials are closely in contact with host biological systems via biomaterial-cell/tissue interactions, and these interactions play pivotal roles in regulating cell functions and tissue regeneration. However, many biomaterials degrade over time, and these degradation products also have been shown to interact with host cells/tissue. Therefore, it may prove useful to specifically design implanted biomaterials with degradation products which greatly improve the performance of the implant. Herein, we report an injectable, citrate-containing polyester hydrogel which can release citrate as a cell regulator via hydrogel degradation and simultaneously show sustained release of an encapsulated growth factor Mydgf. By coupling the therapeutic effect of the hydrogel degradation product (citrate) with encapsulated Mydgf, we observed improved postmyocardial infarction (MI) heart repair in a rat MI model. Intramyocardial injection of our Mydgf-loaded citrate-containing hydrogel was shown to significantly reduce scar formation and infarct size, increase wall thickness and neovascularization, and improve heart function. This bioactive injectable hydrogel-mediated combinatorial approach offers myriad advantages including potential adjustment of delivery rate and duration, improved therapeutic effect, and minimally invasive administration. Our rational design combining beneficial degradation product and controlled release of therapeutics provides inspiration toward the next generation of biomaterials aiming to revolutionize regenerative medicine.

Nanotechnology-Mediated Drug Delivery for the Treatment of Obesity and Its Related Comorbidities.

Obesity is a serious health issue affecting humanity on a global scale. Recognized by the American Medical Association as a chronic disease, the incidence of obesity continues to grow at an accelerating rate and obesity has become one of the major threats to human health. Excessive weight gain is tied to metabolic syndrome, which is shown to increase the risk of chronic diseases, such as heart disease and type 2 diabetes, taxing an already overburdened healthcare system and increasing mortality worldwide. Available treatments such as bariatric surgery and pharmacotherapy are often accompanied by adverse side effects and poor patient compliance. Nanotechnology, an emerging technology with a wide range of biomedical applications, has provided an unprecedented opportunity to improve the treatment of many diseases, including obesity. This review provides an introduction to obesity and obesity-related comorbidities. The most recent developments of nanotechnology-based drug delivery strategies are highlighted and discussed. Additionally, challenges and consideration for the development of nanoformulations with translational potential are discussed. The overall objective of this review is to enhance the understanding of the design and development of nanomedicine for treatments of obesity and related comorbidities.

Boron-doped graphene nanosheet-supported Pt: a highly active and selective catalyst for low temperature H2-SCR.

A series of boron-doped graphene-supported Pt (Pt/BG) nanosheets were designed and synthesized using a one-step facile hydrothermal method. ICP, XPS, and TPD results confirmed that boron atoms were successfully embedded into the graphene matrix. The selective catalytic reduction of nitric oxide with hydrogen (H2-SCR) was tested over Pt/BG catalysts. The multi-roles of doped-boron were investigated by Raman, BET, CO-chemisorption, H2-TPD, XPS, and NO-TPD. Boron doping led to a higher dispersion and smaller size of Pt nanoparticles, facilitated hydrogen spillover, promoted more metallic Pt formation, and increased both H2 and NO chemisorption, which were attributed to an enhanced Pt nucleation rate over doped-boron, electron donation from boron to Pt, and extra chemisorption sites. The reaction performances (conversion 94.7%, selectivity 90.3%, and TOF 0.092 s-1) were greatly promoted attributing to a bifunctional catalytic mechanism. This work paves the way to modify the structure and tune the chemisorption ability of graphene-based catalysts, and provides novel insights for designing high performance catalysts.

Dual-Functional Dextran-PEG Hydrogel as an Antimicrobial Biomedical Material.

Microbial infections continually present a major worldwide public healthcare threat, particularly in instances of impaired wound healing and biomedical implant fouling. The development of new materials with the desired antimicrobial property to avoid and treat wound infection is urgently needed in wound care management. This study reports a novel dual-functional biodegradable dextran-poly(ethylene glycol) (PEG) hydrogel covalently conjugated with antibacterial Polymyxin B and Vancomycin (Vanco). The hydrogel is designed as a specialized wound dressing that eradicates existing bacteria and inhibits further bacteria growth, while, ameliorating the side effects of antibiotics and accelerating tissue repair and regeneration. The hydrogel exhibits potent antibacterial activities against both gram-negative bacteria Escherichia coli (E. coli) and gram-positive bacteria Staphylococcus aureus (S. aureus) with no observable toxicity to mouse fibroblast cell line NIH 3T3. These results demonstrate the immense potential of dextran-PEG hydrogel as a wound dressing healthcare material in efficiently controlling bacteria growth in complex biological systems.

Drug Delivery to the Brain across the Blood-Brain Barrier Using Nanomaterials.

A major obstacle facing brain diseases such as Alzheimer's disease, multiple sclerosis, brain tumors, and strokes is the blood-brain barrier (BBB). The BBB prevents the passage of certain molecules and pathogens from the circulatory system into the brain. Therefore, it is nearly impossible for therapeutic drugs to target the diseased cells without the assistance of carriers. Nanotechnology is an area of growing public interest; nanocarriers, such as polymer-based, lipid-based, and inorganic-based nanoparticles can be engineered in different sizes, shapes, and surface charges, and they can be modified with functional groups to enhance their penetration and targeting capabilities. Hence, understanding the interaction between nanomaterials and the BBB is crucial. In this Review, the components and properties of the BBB are revisited and the types of nanocarriers that are most commonly used for brain drug delivery are discussed. The properties of the nanocarriers and the factors that affect drug delivery across the BBB are elaborated upon in this review. Additionally, the most recent developments of nanoformulations and nonconventional drug delivery strategies are highlighted. Finally, challenges and considerations for the development of brain targeting nanomedicines are discussed. The overall objective is to broaden the understanding of the design and to develop nanomedicines for the treatment of brain diseases.

Highly specific colorimetric detection of DNA oxidation biomarker using gold nanoparticle/triplex DNA conjugates.

DNA oxidation causes a variety of diseases including cancer. The oxidized DNA nucleobases are excised by cellular repair enzymes and released into extracellular fluids. Specifically, the excised DNA oxidation product, such as 8-oxoGua, has been suggested as a biomarker for early cancer diagnosis. We previously developed an artificial receptor for the free base of 8-oxoGua on a triplex DNA backbone. The receptor contained a pre-organized cavity, which bounded 8-oxoGua with strong affinity and excellent selectivity over other nucleobases. However, accurate detection of 8-oxoGua in urine samples was affected by the presence of a large excess of guanine. Herein, we report a strategy to convert our receptor to a colorimetric biosensor by conjugating DNA strands to gold nanoparticles (GNP), specifically for 8-oxoGua. By simply incubating our sensor with a urine sample, 8-oxoGua can be detected at submicromolar concentrations with UV-vis spectrometer or even by naked eye.

Hydrogel as a bioactive material to regulate stem cell fate.

The encapsulation of stem cells in a hydrogel substrate provides a promising future in biomedical applications. However, communications between hydrogels and stem cells is complicated; various factors such as porosity, different polymer types, stiffness, compatibility and degradation will lead to stem cell survival or death. Hydrogels mimic the three-dimensional extracellular matrix to provide a friendly environment for stem cells. On the other hand, stem cells can sense the surroundings to make the next progression, stretching out, proliferating or just to remain. As such, understanding the correlation between stem cells and hydrogels is crucial. In this Review, we first discuss the varying types of the hydrogels and stem cells, which are most commonly used in the biomedical fields and further investigate how hydrogels interact with stem cells from the perspective of their biomedical application, while providing insights into the design and development of hydrogels for drug delivery, tissue engineering and regenerative medicine purpose. In addition, we compare the results such as stiffness, degradation time and pore size as well as peptide types of hydrogels from respected journals. We also discussed most recently magnificent materials and their effects to regulate stem cell fate.