Multi-Scale Photoacoustic Assessment of Wound Healing Using Chitosan-Graphene Oxide Hemostatic Sponge

MXene-NH2/chitosan hemostatic sponges for rapid wound healing

Effective control of wound bleeding and sustained promotion of wound healing remain a major challenge for hemostatic materials. In this study, the hemostatic sponge with controllable antibacterial and adjustable continuous promotion of wound healing (CMNCu) was prepared by chitosan, aminated MXene and copper ion. Interestingly, the internal topological point-line-surface interaction endowed the CMN-Cu sponge longitudinal staggered tubular porous microstructure, combined with the lipophilic properties obtained by modified MXene, which greatly improved its flexibility, wet elasticity and blood enrichment capacity. In addition, the sponge achieved controlled release of active ingredients, which made it present highly effective antibacterial activity and long-lasting ability to promote wound healing. In vitro and in vivo experiments confirmed that CMN-Cu sponge presented high-efficient hemostatic performance. Last but not least, a series of cell experiments showed that the CMN-Cu sponge had excellent safety as a hemostatic material.

Visualization of photothermal therapy by semiconducting polymer dots mediated photoacoustic detection in NIR II

Visualization of photothermal therapy mediated by photothermal transduction agents (PTAs) is important to promote individual treatment of patients with low side effects. Photoacoustic detection has emerged as a promising noninvasive method for the visualization of PTAs distribution but still has limitations in temperature measurement, including poor measurement accuracy and low tissue penetration depth. In this study, we developed biocompatible semiconducting polymer dots (SPD) for in situ coupling of photothermal and photoacoustic detection in the near-infrared II window. SPD has dual photostability under pulsed laser and continuous-wave laser irradiation with a photothermal conversion efficiency of 42.77%. Meanwhile, a strong correlation between the photoacoustic signal and the actual temperature of SPD can be observed. The standard deviation of SPD-mediated photoacoustic thermometry can reach 0.13 °C when the penetration depth of gelatin phantom is 9.49 mm. Preliminary experimental results in vivo show that SPD-mediated photoacoustic signal has a high signal-to-noise ratio, as well as good performance in temperature response and tumor enrichment. Such a study not only offers a new nanomaterial for the visualization of photothermal therapy but will also promote the theranostic platform for clinical applications.

Handheld interventional ultrasound/photoacoustic puncture needle navigation based on deep learning segmentation

Interventional ultrasound (US) has challenges in accurate localization of the puncture needle due to intrinsic acoustic interferences, which lead to blurred, indistinct, and even invisible needles in handheld linear array transducer-based US navigation, especially the incorrect needle tip positioning. Photoacoustic (PA) imaging can provide complementary image contrast, without additional data acquisition. Herein, we proposed an internal illumination to solely light up the needle tip in PA imaging. Then deep-learning-based feature segmentation alleviates acoustic interferences, enhancing the needle shaft-tip visibility. Further, needle shaft-tip compensation aligned the needle shaft in US image and the needle tip in the PA image. The experiments on phantom, ex vivo chicken breast, preclinical radiofrequency ablation and in vivo biopsy of sentinel lymph nodes were piloted. The target registration error can reach the submillimeter level, achieving precise puncture needle tracking ability with in-plane US/PA navigation.

Heavy water coupling gel for short-wave infrared photoacoustic imaging

Significance

Changes in lipid, water, and collagen (LWC) content in tissue are associated with numerous medical abnormalities (cancer, atherosclerosis, and Alzheimer's disease). Standard imaging modalities are limited in resolution, specificity, and/or penetration for quantifying these changes. Short-wave infrared (SWIR) photoacoustic imaging (PAI) has the potential to overcome these challenges by exploiting the unique optical absorption properties of LWC > 1000    nm .

Aim

This study's aim is to harness SWIR PAI for mapping LWC changes in tissue. The focus lies in devising a reflection-mode PAI technique that surmounts current limitations related to SWIR light delivery.

Approach

To enhance light delivery for reflection-mode SWIR PAI, we designed a deuterium oxide (D 2 O , "heavy water") gelatin (HWG) interface for opto-acoustic coupling, intended to significantly improve light transmission above 1200 nm.

Results

HWG permits light delivery > 1    mJ up to 1850 nm, which was not possible with water-based coupling (> 1    mJ light delivery up to 1350 nm). PAI using the HWG interface and the Visualsonics Vevo LAZR-X reveals a signal increase up to 24 dB at 1720 nm in lipid-rich regions.

Conclusions

By overcoming barriers related to light penetration, the HWG coupling interface enables accurate quantification/monitoring of biomarkers like LWC using reflection-mode PAI. This technological stride offers potential for tracking changes in chronic diseases (in vivo) and evaluating their responses to therapeutic interventions.

Chitosan-Based Biomaterials for Hemostatic Applications: A Review of Recent Advances

Hemorrhage is a detrimental event present in traumatic injury, surgery, and disorders of bleeding that can become life-threatening if not properly managed. Moreover, uncontrolled bleeding can complicate surgical interventions, altering the outcome of surgical procedures. Therefore, to reduce the risk of complications and decrease the risk of morbidity and mortality associated with hemorrhage, it is necessary to use an effective hemostatic agent that ensures the immediate control of bleeding. In recent years, there have been increasingly rapid advances in developing a novel generation of biomaterials with hemostatic properties. Nowadays, a wide array of topical hemostatic agents is available, including chitosan-based biomaterials that have shown outstanding properties such as antibacterial, antifungal, hemostatic, and analgesic activity in addition to their biocompatibility, biodegradability, and wound-healing effects. This review provides an analysis of chitosan-based hemostatic biomaterials and discusses the progress made in their performance, mechanism of action, efficacy, cost, and safety in recent years.

A comprehensive review on the applications of carbon-based nanostructures in wound healing: from antibacterial aspects to cell growth stimulation

A wound is defined as damage to the integrity of biological tissue, including skin, mucous membranes, and organ tissues. The treatment of these injuries is an important challenge for medical researchers. Various materials have been used for wound healing and dressing applications among which carbon nanomaterials have attracted significant attention due to their remarkable properties. In the present review, the latest studies on the application of carbon nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), carbon dots (CDs), carbon quantum dots (CQDs), carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds (NDs) in wound dressing applications are evaluated. Also, a variety of carbon-based nanocomposites with advantages such as biocompatibility, hemocompatibility, reduced wound healing time, antibacterial properties, cell-adhesion, enhanced mechanical properties, and enhanced permeability to oxygen has been reported for the treatment of various wounds.

Photoacoustic Imaging Probes for Theranostic Applications

Photoacoustic imaging (PAI), an emerging biomedical imaging technology, capitalizes on a wide range of endogenous chromophores and exogenous contrast agents to offer detailed information related to the functional and molecular content of diseased biological tissues. Compared with traditional imaging technologies, PAI offers outstanding advantages, such as a higher spatial resolution, deeper penetrability in biological tissues, and improved imaging contrast. Based on nanomaterials and small molecular organic dyes, a huge number of contrast agents have recently been developed as PAI probes for disease diagnosis and treatment. Herein, we report the recent advances in the development of nanomaterials and organic dye-based PAI probes. The current challenges in the field and future research directions for the designing and fabrication of PAI probes are proposed.

Shear-thinning and self-healing chitosan-graphene oxide hydrogel for hemostasis and wound healing

Hydrogels with injectability, self-healing ability and adhesiveness have great potential for hemostasis and full-thickness skin wound repair, which are usually fabricated by multistep chemical synthesis and the use of organic solvents and catalyst. Herein, we report an injectable and self-healing hydrogel facilely prepared through one-pot heating of chitosan and graphene oxide mixture solution, without any pollutant and waste generated. The dynamic reversible breakage and recombination of noncovalent bonds between chitosan and graphene oxide endows the hydrogel injectability and self-healing ability. In addition, the mechanical and rheological properties of the hydrogels can be controlled by varying the dosage of graphene oxide. Meanwhile, hydrogels exhibited good adhesiveness and hemocompatibility. Finally, in vivo experiments in a rat liver bleeding model and full-thickness skin defect model verified the outstanding hemostatic and wound healing capability of the hydrogels, indicating the promising future for use as wound dressing.