Retrograde labeling of the rat facial nerve with carbocyanine dyes to enhance intraoperative identification

Advances in optical molecular imaging for neural visualization

Iatrogenic nerve injury is a significant complication in surgery, which can negatively impact patients' quality of life. Currently, the main clinical neuroimaging methods, such as computed tomography, magnetic resonance imaging, and high-resolution ultrasonography, do not offer precise real-time positioning images for doctors during surgery. The clinical application of optical molecular imaging technology has led to the emergence of new concepts such as optical molecular imaging surgery, targeted surgery, and molecular-guided surgery. These advancements have made it possible to directly visualize surgical target areas, thereby providing a novel method for real-time identification of nerves during surgery planning. Unlike traditional white light imaging, optical molecular imaging technology enables precise positioning and identifies the cation of intraoperative nerves through the presentation of color images. Although a large number of experiments and data support its development, there are few reports on its actual clinical application. This paper summarizes the research results of optical molecular imaging technology and its ability to realize neural visualization. Additionally, it discusses the challenges neural visualization recognition faces and future development opportunities.

Targeting Small Molecule Delivery to the Brain and Spinal Cord via Intranasal Administration of Rabies Virus Glycoprotein (RVG29)-Modified PLGA Nanoparticles

Alternative routes of administration are one approach that could be used to bypass the blood–brain barrier (BBB) for effective drug delivery to the central nervous system (CNS). Here, we focused on intranasal delivery of polymer nanoparticles. We hypothesized that surface modification of poly(lactic-co-glycolic acid) (PLGA) nanoparticles with rabies virus glycoprotein (RVG29) would increase residence time and exposure of encapsulated payload to the CNS compared to non-targeted nanoparticles. Delivery kinetics and biodistribution were analyzed by administering nanoparticles loaded with the carbocyanine dye 1,1′-Dioctadecyl-3,3,3′,3′-Tetramethylindotricarbocyanine Iodide (DiR) to healthy mice. Intranasal administration yielded minimal exposure of nanoparticle payload to most peripheral organs and rapid, effective delivery to whole brain. Regional analysis of payload delivery within the CNS revealed higher delivery to tissues closest to the trigeminal nerve, including the olfactory bulb, striatum, midbrain, brainstem, and cervical spinal cord. RVG29 surface modifications presented modest targeting benefits to the striatum, midbrain, and brainstem 2 h after administration, although targeting was not observed 30 min or 6 h after administration. Payload delivery to the trigeminal nerve was 3.5× higher for targeted nanoparticles compared to control nanoparticles 2 h after nanoparticle administration. These data support a nose-to-brain mechanism of drug delivery that closely implicates the trigeminal nerve for payload delivery from nanoparticles via transport of intact nanoparticles and eventual diffusion of payload. Olfactory and CSF routes are also observed to play a role. These data advance the utility of targeted nanoparticles for nose-to-brain drug delivery of lipophilic payloads and provide mechanistic insight to engineer effective delivery vectors to treat disease in the CNS.

Use of embryonic fibroblasts associated with graphene quantum dots for burn wound healing in Wistar rats

Burn is one of the common wounds in the world and using modern methods such as cell therapy can be considered as an effective strategy in the treatment of these wounds. The aim of this study is investigating the effects of using graphene quantum dots (GQDs) associated fibroblasts on treating third-degree burns in Wistar rats. In this experiment, cells were obtained by isolating fibroblasts from 13-day embryos of Wistar rats. MTT assay was performed to determine the dose of nanoparticle and cell tracker. For this study, 40 Wistar rats were burned and randomly divided into two groups of control and treatment. The treatment group was divided into three groups of daily injection of GQD nanoparticle with a concentration of 100 μg/ml, cell therapy, and cell therapy + GQDs. On days 20 and 40, skin tissue sections were prepared and stained with hematoxylin-eosin (H&E) and trichrome Masson for microscopic examination. Macroscopic and microscopic observations showed that in the treatment groups, the recovery was higher than the control. Also, cell therapy and GQD injection and simultaneous injection of cell therapy + GQDs accelerated the wound healing process and the cell therapy + GQDs were significantly more effective than nanoparticles and cell injection alone after 20 and 40 days. Histological studies indicated a significant increase in angiogenesis, number of cells, collagen synthesis, thickness of skin layers, and ultimately acceleration wound healing in treatment samples compared to controls. Based on these results, it can be concluded that simultaneous cell therapy and GQDs accelerate the repair of skin lesions in the animal models more significantly.