Fabrication of Tip-Dissolving Microneedles for Transdermal Drug Delivery of Meloxicam

Dissolving microneedles (MNs) offered a simple, minimally invasive method for meloxicam (MX) delivery to the skin. However, the fabrication of dissolving MNs still faced some challenges, such as significant time consumption, loss of drug activity, and difficulty in regulating MN drug loading. To address these issues, we developed the tip-dissolving (TD) MNs. Several kinds of drugs were encapsulated successfully, and the quantity of MX ranged from 37.23?±?8.40 to 332.53?±?13.37 μg was precisely controlled. The effects of fabrication process on biomacromolecules stability were studied, and it was found that tyrosinase kept 90.4% activity during the fabrication process. The whole process for the fabrication of MNs only takes approximately 1 h. In order to further evaluate the potential of the TD MNs, MX TD MNs were prepared for in vitro release experiments, in vivo release experiments, safety evaluation, pharmacokinetic studies, and pharmacodynamic studies. The results demonstrated that MX TD MNs offered several advantages, including rapid release of the encapsulated drug (91.72% within 30 min), efficient drug delivery to skin (79.18%), no obvious skin irritation, decent relative bioavailability (122.3%), and strong anti-inflammatory and analgesic effects. Based on these results, we envisage that the TD MNs have promising potential for transdermal drug delivery of MX.     

Positive effects of low-dose photodynamic therapy with aminolevulinic acid or its methyl ester in skin rejuvenation and wound healing: An update

In dermatology, photodynamic therapy (PDT) is widely used in skin tumors, infections, etc., because of the killing effect triggered by toxic reactive oxygen species (ROS). However, the ROS concentration is determined by various photosensitizer concentrations and formulations, as well as various irradiation parameters. Low-dose PDT leads to sufficiently low ROS level, which results in biological effects that are the exact opposite of the killing potency. Therefore, in recent years, low-dose PDT has been exploited in improving aging and wound. Low-dose ALA/MAL PDT might improve aging through promoting the proliferation of fibroblasts, blocking DNA damage, counteracting oxidative stress, inhibiting melanogenesis, and remodeling lymphatic vessels in aged skin. Promoting fibroblasts and epidermal stem cells proliferation and migration, promoting granulation tissue formation and angiogenesis and regulating the inflammatory process might be the mechanisms of low-dose ALA/MAL PDT in wound healing. Nevertheless, the positive effects of low-dose PDT have not been thoroughly investigated in dermatology, and high-quality studies are still needed to fill the relevant vacancy.     

Assessment of ALA‐induced PpIX production in porcine skin pretreated with microneedles

Photodynamic therapy (PDT) is used for skin treatments of premalignant and cancer lesions and recognized as a non‐invasive technique that combines tissue photosensitization and subsequent exposure to light to induce cell death. However, it is limited to the treatment of superficial lesions, mainly due to the low cream penetration. Therefore, the improvement of transdermal distribution of aminolevulinic acid (ALA) is needed. In this study, the kinetics and homogeneity of production of ALA‐induced PpIX after the skin pre‐treatment with microneedles rollers of 0.5, 1.0 and 1.5 mm length were investigated. An improvement in homogeneity and production of PpIX was shown in a porcine model.

Widefield fluorescence imaging three hours after the topical application of ALA‐cream in the combined treatment with microeedles rollers.     

Dependence of laser-induced optical breakdown on skin type during 1064 nm picosecond laser treatment

The current study aims to evaluate the dependence of laser-induced optical breakdown (LIOB) on skin types by using 1064 nm picosecond laser with micro-lens arrays (MLA) and diffractive optical elements (DOE). Both black and white skin tissues were examined to comparatively assess the LIOB effects in the skin in terms of laser-induced vacuolization. The black skin irradiated at 3.0 J/cm² demonstrated that MLA yielded a deeper distribution (180-400 μm) of laser-induced vacuoles with a size of 67 μm, compared to DOE (180-280 μm; 40 μm in size). However, the white skin presented that MLA created larger vacuoles (134 μm in size) in a smaller number at deeper distributions (125-700 μm) than MLA with the black skin. DOE generated no laser-induced vacuolization in the white skin. The white skin tissue with inherent higher scattering could be responsible for deeper vacuolization after the picosecond laser treatment. Further investigations are expected to determine the optimal treatment conditions for various skin types.     

Integrated effects of fractional laser microablation and sonophoresis on skin immersion optical clearing in vivo

This study is aimed to find an approach for effective skin optical clearing in vivo using polyethylene glycol 300 (PEG‐300) as an optical clearing agent in combination with physical enhancers: fractional laser microablation (FLMA) and/or low‐frequency sonophoresis. In this study albino outbred rats were used. Light attenuation coefficient and optical clearing potential (OCP) of these approaches were evaluated in upper (from ~70 to ~200 μm) and middle (from ~200 to ~400 μm) dermis separately using optical coherence tomography. In 30 minutes, OCP of sonophoresis in combination with FLMA and PEG‐300 in the upper dermis was the maximal (2.3 ± 0.4) in comparison with other treatments in this time point. The most effective approach for optical clearing of middle dermis was PEG‐300 and sonophoresis; but the maximal value of OCP (1.6 ± 0.1) was achieved only in 90 minutes.     

A modification for the calculation of water depth profiles in oil‐treated skin by in vivo confocal Raman microscopy

In this study, an extended calculation method for the determination of the water profiles in oil‐treated skin is proposed, which is based on the calculation of the ratio between the Raman band intensities of water (3350‐3550 cm^?1) and keratin Amide I at 1650 cm^?1. The proposed method is compared with the conventional method based on the ratio of the Raman band intensities of water (3350‐3550 cm^?1) and keratin at 2930 cm^?1. The conventional method creates artifacts in the depth profiles of the water concentration in oil‐treated skin, showing a lower amount of water in the upper and intermediate layers of the stratum corneum, which is due to the superposition of oil‐ and keratin‐related Raman bands at 2930 cm^?1. The proposed extended method shows no artifacts and has the potential to determine the water depth profiles after topical application of formulations on the skin.     

Exploring the utility of Deep Red Anthraquinone 5 for digital staining of ex vivo confocal micrographs of optically sectioned skin

We investigated the utility of the fluorescent dye Deep Red Anthraquinone 5 (DRAQ5) for digital staining of optically sectioned skin in comparison to acridine orange (AO). Eight fresh-frozen thawed Mohs discard tissue specimens were stained with AO and DRAQ5, and imaged using an ex vivo confocal microscope at three wavelengths (488 nm and 638 nm for fluorescence, 785 nm for reflectance). Images were overlaid (AO + Reflectance, DRAQ5 + Reflectance), digitally stained, and evaluated by three investigators for perceived image quality (PIQ) and histopathological feature identification. In addition to nuclear staining, AO seemed to stain dermal fibers in a subset of cases in digitally stained images, while DRAQ5 staining was more specific to nuclei. Blinded evaluation showed substantial agreement, favoring DRAQ5 for PIQ (82%, Cl 75%-90%, Gwet's AC 0.74) and for visualization of histopathological features in (81%, Cl 73%-89%, Gwet's AC 0.67), supporting its use in digital staining of multimodal confocal micrographs of skin.     

Fine-tuning the encapsulation of a photosensitizer in nanoparticles reveals the relationship between internal structure and phototherapeutic effects

Photodynamic therapy (PDT) is a cancer therapy that uses a photosensitizer (PS) in the presence of oxygen molecules. Since singlet oxygen is highly reactive, it is important to deliver it to the target site. Thus, an efficient drug delivery system (DDS) is essential for enhancing the efficacy of such a treatment and protecting against the side effects of PDT. Here, we report on attempts to increase the therapeutic effect of PDT by using a DDS, a lipid nanoparticle (LNP). We prepared a porphyrin analog, rTPA (PS) that was encapsulated in LNPs using a microfluidic device. The findings indicated that the internal structure of the prepared particles changed depending on the amount of rTPA in LNPs. The photoactivity and cell-killing effect of PS in LNPs also changed when the amount of the cargo increased. These results suggest that the internal structure of LNPs is important factors that affect drug efficacy.     

Die V?gel B?hmens

Ohne ZusammenfassungHerr Dr. Fritsch, Verfasser des kürzlich vollendeten bekannten Werkes die Vögel Europas, veröffentlicht gegenwärtig, gestützt auf langjährige Erfahrungen, in dem Archiv für die naturwissenschaftliche Landesdurchforschung von Röhmen eine schätzenswerthe Zusammenstellung der Wirbelthiere Böhmens. Das Folgende begreift die Abtheilung der Vögel. Indem wir dieselbe dem ornithologischen Publikum zugänglich zu machen wünschen, verweisen wir für die Synonymie und das Weitere in Bezug der einzelnen Arten zugleich gern auf das oben augeführte ausführliche Werk des Verfassers.     

Polarization-resolved SHG imaging as a fast screening method for collagen alterations during aging: Comparison with light and electron microscopy

Our previous study on rat skin showed that cumulative oxidative pressure induces profound structural and ultrastructural alterations in both rat skin epidermis and dermis during aging. Here, we aimed to investigate the biophotonic properties of collagen as a main dermal component in the function of chronological aging. We used second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) on 5 μm thick skin paraffin sections from 15-day-, 1-month- and 21-month-old rats, respectively, to analyze collagen alterations, in comparison to conventional light and electron microscopy methods. Obtained results show that polarization-resolved SHG (PSHG) images can detect collagen fiber alterations in line with chronological aging and that this method is consistent with light and electron microscopy. Moreover, the β coefficient calculated from PSHG images points out that delicate alterations lead to a more ordered structure of collagen molecules due to oxidative damage. The results of this study also open the possibility of successfully applying this fast and label-free method to previously fixed samples.     

Gingivitis resolution followed by optical coherence tomography and fluorescence imaging: A case study

Gingivitis is highly prevalent in adults, and if left untreated, can progress to periodontitis. In this article, we present an interesting case study where the resolution of gingivitis was followed over a period of 10 days using optical coherence tomography (OCT) and light-induced autofluorescence (LIAF). We demonstrate that OCT and its functional angiography can distinctively capture the changes during the resolution of gingivitis; while LIAF can detect red-fluorescent signals associated with mature plaque present at the inflamed site. The acute inflammatory region showed evidence of angiogenesis based on the quantification of vessel density and number; while no angiogenesis was detected within the less inflamed region. Gingival thickness showed a reduction of 140 ± 26 μm on average, measured between the peak gingivitis event and the period wherein the inflammation was resolved. Vessels in the angiogenesis site was found to reduce exponentially. The mildly inflamed site showed a decreasing trend in the vessel size, which however was within the error of the measurement.     

Enhanced spatial resolution for snapshot hyperspectral imaging of blood perfusion and melanin information within human tissue

We report a reconstruction method to achieve high spatial resolution for hyperspectral imaging of chromophore features in skin in vivo. The method utilizes an established structure‐adaptive normalized convolution algorithm to reconstruct high spatial resolution of hyperspectral images from snapshot low‐resolution hyperspectral image sequences captured by a snapshot spectral camera. The reconstructed images at chromophore‐sensitive wavebands are used to map the skin features of interest. We demonstrate the method experimentally by mapping the blood perfusion and melanin features (moles) on the facial skin. The method relaxes the constrains of the relatively low spatial resolution in the snapshot hyperspectral camera, making it more usable in imaging applications.     

Stereotaxic endoscopy for the ocular imaging of awake,freely moving animal models

Stereotaxic instruments are increasingly used in research animals for the study of disease, but typically require restraints and anesthetic procedures. A stereotaxic head mount that enables imaging of the anterior chamber of the eye in alert and freely mobile mice is presented in this study. The head mount is fitted based on computed tomography scans and manufactured using 3D printing. The system is placed noninvasively using temporal mount bars and a snout mount, without breaking the skin or risking suffocation, while an instrument channel stabilizes the ocular probes. With a flexible micro‐endoscopic probe and a confocal scanning laser microscopy system, <20 μm resolution is achieved in vivo with a field of view of nearly 1 mm. Discomfort is minimal, and further adaptations for minimally invasive neuroscience, optogenetics and auditory studies are possible.     

Intraoperative detection of IDH-mutant glioma using fluorescence lifetime imaging

Identifying isocitrate dehydrogenase (IDH)-mutation and glioma subtype during surgery instead of days later can aid in modifying tumor resection strategies for better survival outcomes. We report intraoperative identification of IDH-mutant glioma (N = 12 patients) with a clinically compatible fluorescence lifetime imaging (FLIm) device (excitation: 355 nm; emission spectral bands: 390/40 nm, 470/28 nm, 542/50 nm). The fluorescence-derived parameters were analyzed to study the optical contrast between IDH-mutant tumors and surrounding brain tissue. IDH-mutant oligodendrogliomas exhibited shorter lifetimes (3.3 ± 0.1 ns) than IDH-mutant astrocytomas (4.1 ± 0.1 ns). Both IDH-mutant glioma subtypes had shorter lifetimes than white matter (4.6 ± 0.4 ns) but had comparable lifetimes to cortex. Lifetimes also increased with malignancy grade within IDH-mutant oligodendrogliomas (grade 2: 2.96 ± 0.08 ns, grade 3: 3.4 ± 0.3 ns) but not within IDH-mutant astrocytomas. The current results support the feasibility of FLIm as a surgical adjuvant for identifying IDH-mutant glioma tissue.     

Miniaturized all fiber probe for optical coherence tomography and pH detection of biological tissue

We present a novel all-fiber probe with 710-μm outside diameter for combined optical coherence tomography and pH detection. In cancer surgery, a significant challenge is how to completely remove the malignant tumor without cutting too much normal tissue. The difference between cancer tissue and normal tissue not only lies in morphology and structure but also in tissue pH, where malignant tissue has a lower pH. This dual-modality probe combined optical coherence tomography and pH detection of biological tissue, is expected to determine whether the tissue is cancerous quickly and accurately. The probe utilizes a typical three-segment structure (double-clad fiber - no-core fiber - graded-index fiber). We obtained a lateral resolution of ~10.6 μm, a working distance of ~506 μm and a pH measurement accuracy of 0.01 pH unit for the probe. The performance of the all-fiber probe was verified through an ex vivo experiment using the porcine brain specimen.     

A novel automatic 3D stitching algorithm for optical coherence tomography angiography and its application in dermatology

Optical coherence tomography (OCT) and OCT angiography (OCTA) techniques offer numerous advantages in clinical skin applications but the field of view (FOV) of current commercial systems are relatively limited to cover the entire skin lesion. The typical method to expand the FOV is to apply wide field objective lens. However, lateral resolution is often sacrificed when scanning with these lenses. To overcome this drawback, we developed an automated 3D stitching method for creating high-resolution skin structure and vascular volumes with large field of view, which was realized by montaging multiple adjacent OCT and OCTA volumes. The proposed stitching method is demonstrated by montaging 3 × 3 OCT and OCTA volumes (nine OCT/OCTA volumes as one data set with each volume covers 2.5 cm × 2.5 cm area) of healthy thin and thick skin from six volunteers. The proposed stitching protocol achieves high flexibility and repeatable for all the participants. Moreover, according to evaluation of structural similarity index and feature similarity index, our proposed stitched result has a superior similarity to single scanning protocol in large-scaled. We had also verified its improved performance through assessing metrics of vessel contrast-noise-ratio (CNR) from 2.07 ± 0.44 (single large-scaled scanning protocol) to 3.05 ± 0.51 (proposed 3 × 3 sub-volume stitching method).     

Impact of optical clearing on ex vivo human skin optical properties characterized by spatially resolved multimodal spectroscopy

A spatially resolved multimodal spectroscopic device was used on a two-layered “hybrid” model made of ex vivo skin and fluorescent gel to investigate the effect of skin optical clearing on the depth sensitivity of optical spectroscopy. Time kinetics of fluorescence and diffuse reflectance spectra were acquired in four experimental conditions: with optical clearing agent (OCA) 1 made of polyethylene glycol 400 (PEG-400), propylene glycol and sucrose; with OCA 2 made of PEG-400 and dimethyl sulfoxide (DMSO); with saline solution as control and a “dry” condition. An increase in the gel fluorescence back reflected intensity was measured after optical clearing. Effect of OCA 2 turned out to be stronger than that of OCA 1, possibly due to DMSO impact on the stratum corneum keratin conformation. Complementary experimental results showed increased light transmittance through the skin and confirmed that the improvement in the depth sensitivity of the multimodal spectroscopic approach is related not only to the dehydration and refractive indices matching due to optical clearing, but also to the mechanical compression of tissues caused by the application of the spectroscopic probe.     

In situ measurement of the isoplanatic patch for imaging through intact bone

Wavefront-shaping (WS) enables imaging through scattering tissues like bone, which is important for neuroscience and bone-regeneration research. WS corrects for the optical aberrations at a given depth and field-of-view (FOV) within the sample; the extent of the validity of which is limited to a region known as the isoplanatic patch (IP). Knowing this parameter helps to estimate the number of corrections needed for WS imaging over a given FOV. In this paper, we first present direct transmissive measurement of murine skull IP using digital optical phase conjugation based focusing. Second, we extend our previously reported phase accumulation ray tracing (PART) method to provide in-situ in-silico estimation of IP, called correlative PART (cPART). Our results show an IP range of 1 to 3 μm for mice within an age range of 8 to 14 days old and 1.00 ± 0.25 μm in a 12-week old adult skull. Consistency between the two measurement approaches indicates that cPART can be used to approximate the IP before a WS experiment, which can be used to calculate the number of corrections required within a given field of view.     

Sentinel lymph node detection by combining nonradioactive techniques with contrast agents: State of the art and prospects

The status of sentinel lymph nodes (SLNs) has a substantial prognostic value because these nodes are the first place where cancer cells accumulate along their spreading route. Routine SLN biopsy (“gold standard”) involves peritumoral injections of radiopharmaceuticals, such as technetium-99m, which has obvious disadvantages. This review examines the methods used as “gold standard” analogs to diagnose SLNs. Nonradioactive preoperative and intraoperative methods of SLN detection are analyzed. Promising photonic tools for SLNs detection are reviewed, including NIR-I/NIR-II fluorescence imaging, photoswitching dyes for SLN detection, in vivo photoacoustic detection, imaging and biopsy of SLNs. Also are discussed methods of SLN detection by magnetic resonance imaging, ultrasonic imaging systems including as combined with photoacoustic imaging, and methods based on the magnetometer-aided detection of superparamagnetic nanoparticles. The advantages and disadvantages of nonradioactive SLN-detection methods are shown. The review concludes with prospects for the use of conservative diagnostic methods in combination with photonic tools.