Assessing the Safety and Therapeutic Efficacy of Cannabidiol Lipid Nanoparticles in Alleviating Metabolic and Memory Impairments and Hippocampal Histopathological Changes in Diabetic Parkinson's Rats.

Diabetic Parkinson's disease (DP) is a progressive neurodegenerative disease with metabolic syndrome that is increasing worldwide. Emerging research suggests that cannabidiol (CBD) is a neuropharmacological compound that acts against this disease, especially CBD in nano-formulation. The safety of cannabidiol lipid nanoparticles (CBD-LNP) was evaluated by assessing in vitro cytotoxicity in neurons and therapeutic outcomes in a DP animal model, including metabolic parameters and histopathology. CBD-LNPs were fabricated by using a microfluidization technique and showed significantly lower cytotoxicity than the natural form of CBD. The DP rats were induced by streptozotocin followed by a 4-week injection of MPTP with a high-fat diet. Rats were treated orally with a vehicle, CBD, CBD-LNP, or levodopa for 4 weeks daily. As a result, vehicle-treated rats exhibited metabolic abnormalities, decreased striatal dopamine levels, and motor and memory deficits. CBD-LNP demonstrated reduced lipid profiles, enhanced insulin secretion, and restored dopamine levels compared to CBD in the natural form. CBD-LNP also had comparable efficacy to levodopa in ameliorating motor deficits and memory impairment in behavior tests. Interestingly, CBD-LNP presented migration of damaged neuronal cells in the hippocampus more than levodopa. These findings suggest that CBD-LNP holds promise as an intervention addressing both metabolic and neurodegenerative aspects of DP, offering a potential therapeutic strategy.

An efficient and simple SERS approach for trace analysis of tetrahydrocannabinol and cannabinol and multi-cannabinoid detection.

Many countries have legalized cannabis and its derived products for multiple purposes. Consequently, it has become necessary to develop a rapid, effective, and reliable tool for detecting delta-9-tetrahydrocannabinol (THC) and cannabinol (CBN), which are important biologically active compounds in cannabis. Herein, we have fabricated SERS chips by using glancing angle deposition and tuned dimensions of silver nanorods (AgNRs) for detecting THC and CBN at low concentrations. Experimental and computational results showed that the AgNR substrate with film thickness (or nanorod length) of 150 nm, corresponding to nanorod diameter of 79 nm and gap between nanorods of 23 nm, can effectively sense trace THC and CBN with good reproducibility and sensitivity. Due to limited spectral studies of the cannabinoids in previous reports, this work also explored towards identifying characteristic Raman lines of THC and CBN. This information is critical to further reliable data analysis and interpretation. Moreover, multianalyte detection of THC and CBN in a mixture was successfully demonstrated by applying an open-source independent component analysis (ICA) model. The overall method is fast, sensitive, and reliable for sensing trace THC and CBN. The SERS chip-based method and spectral results here are useful for a variety of cannabis testing applications, such as product screening and forensic investigation.

In Vivo Chemical Monitoring at High Spatiotemporal Resolution Using Microfabricated Sampling Probes and Droplet-Based Microfluidics Coupled to Mass Spectrometry.

An essential approach for in vivo chemical monitoring is to use sampling probes coupled with analytical methods; however, this method traditionally has limited spatial and temporal resolution. To address this problem, we developed an analytical system that combines microfabricated push-pull sampling probes with droplet-based microfluidics. The microfabricated probe provides spatial resolution approximately 1000-fold better than that of common microdialysis probes. Microfabrication also facilitated integration of an extra channel into the probe for microinjection. We created microfluidic devices and interfaces that allowed manipulation of nanoliter droplet samples collected from the microfabricated probe at intervals of a few seconds. Use of droplet-based microfluidics prevented broadening of collected zones, yielding 6 s temporal resolution at 100 nL/min perfusion rates. Resulting droplets were analyzed by direct infusion nanoelectrospray ionization (nESI) mass spectrometry for simultaneous determination of glutamine, glutamate, γ-aminobutyric acid, and acetylcholine. Use of low infusion rates that enabled nESI (50 nL/min) was critical to allowing detection in the complex samples. Addition of 13C-labeled internal standards to the droplet samples was used for improved quantification. Utility of the overall system was demonstrated by monitoring dynamic chemical changes evoked by microinjection of high potassium concentrations into the brain of live rats. The results showed stimulated neurochemical release with rise times of 15 s. This work demonstrates the potential of coupling microfabricated sampling probes to droplet-based mass spectrometric assays for studying chemical dynamics in a complex microenvironment at high spatiotemporal resolution.

Microfabricated Probes for Studying Brain Chemistry: A Review.

Probe techniques for monitoring in vivo chemistry (e.g., electrochemical sensors and microdialysis sampling probes) have significantly contributed to a better understanding of neurotransmission in correlation to behaviors and neurological disorders. Microfabrication allows construction of neural probes with high reproducibility, scalability, design flexibility, and multiplexed features. This technology has translated well into fabricating miniaturized neurochemical probes for electrochemical detection and sampling. Microfabricated electrochemical probes provide a better control of spatial resolution with multisite detection on a single compact platform. This development allows the observation of heterogeneity of neurochemical activity precisely within the brain region. Microfabricated sampling probes are starting to emerge that enable chemical measurements at high spatial resolution and potential for reducing tissue damage. Recent advancement in analytical methods also facilitates neurochemical monitoring at high temporal resolution. Furthermore, a positive feature of microfabricated probes is that they can be feasibly built with other sensing and stimulating platforms including optogenetics. Such integrated probes will empower researchers to precisely elucidate brain function and develop novel treatments for neurological disorders.

Design and microfabrication of a miniature fiber optic probe with integrated lenses and mirrors for Raman and fluorescence measurements.

Fiber optics coupled to components such as lenses and mirrors have seen extensive use as probes for Raman and fluorescence measurements. Probes can be placed directly on or into a sample to allow for simplified and remote application of these optical techniques. The size and complexity of such probes however limits their application. We have used microfabrication in polydimethylsiloxane (PDMS) to create compact probes that are 0.5 mm thick by 1 mm wide. The miniature probes incorporate pre-aligned mirrors, lenses, and two fiber optic guides to allow separate input and output optical paths suitable for Raman and fluorescence spectroscopy measurements. The fabricated probe has 70 % unidirectional optical throughput and generates no spectral artifacts in the wavelength range of 200 to 800 nm. The probe is demonstrated for measurement of fluorescence within microfluidic devices and collection of Raman spectra from a pharmaceutical tablet. The fluorescence limit of detection was 6 nM when using the probe to measure resorufin inside a 150-µm inner diameter glass capillary, 100 nM for resorufin in a 60-µm-deep × 100-µm-wide PDMS channel, and 11 nM for fluorescein in a 25-µm-deep × 80-µm-wide glass channel. It is demonstrated that the same probe can be used on different sample types, e.g., microfluidic chips and tablets. Compared to existing Raman and fluorescence probes, the microfabricated probes enable measurement in smaller spaces and have lower fabrication cost. Graphical abstract A microfabricated spectroscopic probe with integrated optics was developed for chemical detection in small spaces and in remote applications.

Microfabrication and in Vivo Performance of a Microdialysis Probe with Embedded Membrane.

Microdialysis sampling is an essential tool for in vivo neurochemical monitoring. Conventional dialysis probes are over 220 µm in diameter and have limited flexibility in design because they are made by assembly using preformed membranes. The probe size constrains spatial resolution and governs the amount of tissue damaged caused by probe insertion. To overcome these limitations, we have developed a method to microfabricate probes in Si that are 45 µm thick × 180 µm wide. The probes contain a buried, U-shaped channel that is 30 µm deep × 60 µm wide and terminates in ports for external connection. A 4 mm length of the probe is covered with a 5 µm thick nanoporous membrane. The membrane was microfabricated by deep reactive ion etching through a porous aluminum oxide layer. The microfabricated probe has cross-sectional area that is 79% less than that of the smallest conventional microdialysis probes. The probes yield 2-20% relative recovery at 100 nL/min perfusion rate for a variety of small molecules. The probe was successfully tested in vivo by sampling from the striatum of live rats. Fractions were collected at 20 min intervals (2 µL) before and after an intraperitoneal injection of 5 mg/kg amphetamine. Analysis of fractions by liquid chromatography-mass spectrometry revealed reliable detection of 14 neurochemicals, including dopamine and acetylcholine, at basal conditions. Amphetamine evoked a 43-fold rise in dopamine, a result nearly identical to a conventional dialysis probe in the same animal. The microfabricated probes have potential for sampling with higher spatial resolution and less tissue disruption than conventional probes. It may also be possible to add functionality to the probes by integrating other components, such as electrodes, optics, and additional channels.