Fluorescence imaging of tryptophan and collagen cross-links to evaluate wound closure ex vivo

Author(s):  
Ying Wang ◽  
Antonio Ortega-Martinez ◽  
Bill Farinelli ◽  
R. R. Anderson ◽  
Walfre Franco
2020 ◽  
Vol 117 (27) ◽  
pp. 15497-15503 ◽  
Author(s):  
Xiaoyu Chen ◽  
Hyunwoo Yuk ◽  
Jingjing Wu ◽  
Christoph S. Nabzdyk ◽  
Xuanhe Zhao

Bioadhesives such as tissue adhesives, hemostatic agents, and tissue sealants have potential advantages over sutures and staples for wound closure, hemostasis, and integration of implantable devices onto wet tissues. However, existing bioadhesives display several limitations including slow adhesion formation, weak bonding, low biocompatibility, poor mechanical match with tissues, and/or lack of triggerable benign detachment. Here, we report a bioadhesive that can form instant tough adhesion on various wet dynamic tissues and can be benignly detached from the adhered tissues on demand with a biocompatible triggering solution. The adhesion of the bioadhesive relies on the removal of interfacial water from the tissue surface, followed by physical and covalent cross-linking with the tissue surface. The triggerable detachment of the bioadhesive results from the cleavage of bioadhesive’s cross-links with the tissue surface by the triggering solution. After it is adhered to wet tissues, the bioadhesive becomes a tough hydrogel with mechanical compliance and stretchability comparable with those of soft tissues. We validate in vivo biocompatibility of the bioadhesive and the triggering solution in a rat model and demonstrate potential applications of the bioadhesive with triggerable benign detachment in ex vivo porcine models.


Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 428
Author(s):  
Emma Renard ◽  
Estel Collado Camps ◽  
Coline Canovas ◽  
Annemarie Kip ◽  
Martin Gotthardt ◽  
...  

Variable domains of heavy chain only antibodies (VHHs) are valuable agents for application in tumor theranostics upon conjugation to both a diagnostic probe and a therapeutic compound. Here, we optimized site-specific conjugation of the chelator DTPA and the photosensitizer IRDye700DX to anti-epidermal growth factor receptor (EGFR) VHH 7D12, for applications in nuclear imaging and photodynamic therapy. 7D12 was site-specifically equipped with bimodal probe DTPA-tetrazine-IRDye700DX using the dichlorotetrazine conjugation platform. Binding, internalization and light-induced toxicity of DTPA-IRDye700DX-7D12 were determined using EGFR-overexpressing A431 cells. Finally, ex vivo biodistribution of DTPA-IRDye700DX-7D12 in A431 tumor-bearing mice was performed, and tumor homing was visualized with SPECT and fluorescence imaging. DTPA-IRDye700DX-7D12 was retrieved with a protein recovery of 43%, and a degree of labeling of 0.56. Spectral properties of the IRDye700DX were retained upon conjugation. 111In-labeled DTPA-IRDye700DX-7D12 bound specifically to A431 cells, and they were effectively killed upon illumination. DTPA-IRDye700DX-7D12 homed to A431 xenografts in vivo, and this could be visualized with both SPECT and fluorescence imaging. In conclusion, the dichlorotetrazine platform offers a feasible method for site-specific dual-labeling of VHH 7D12, retaining binding affinity and therapeutic efficacy. The flexibility of the described approach makes it easy to vary the nature of the probes for other combinations of diagnostic and therapeutic compounds.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shanshan Hu ◽  
Xibo Pei ◽  
Lunliang Duan ◽  
Zhou Zhu ◽  
Yanhua Liu ◽  
...  

AbstractAdministration of drugs via the buccal route has attracted much attention in recent years. However, developing systems with satisfactory adhesion under wet conditions and adequate drug bioavailability still remains a challenge. Here, we propose a mussel-inspired mucoadhesive film. Ex vivo models show that this film can achieve strong adhesion to wet buccal tissues (up to 38.72 ± 10.94 kPa). We also demonstrate that the adhesion mechanism of this film relies on both physical association and covalent bonding between the film and mucus. Additionally, the film with incorporated polydopamine nanoparticles shows superior advantages for transport across the mucosal barrier, with improved drug bioavailability (~3.5-fold greater than observed with oral delivery) and therapeutic efficacy in oral mucositis models (~6.0-fold improvement in wound closure at day 5 compared with that observed with no treatment). We anticipate that this platform might aid the development of tissue adhesives and inspire the design of nanoparticle-based buccal delivery systems.


Author(s):  
Kamonnaree Chotinantakul ◽  
Chavaboon Dechsukhum ◽  
Duangnapa Dejjuy ◽  
Wilairat Leeanansaksiri

AbstractDiabetes can impair wound closure, which can give rise to major clinical problems. Most treatments for wound repair in diabetes remain ineffective. This study aimed to investigate the influence on wound closure of treatments using expanded human cord blood CD34+ cells (CB-CD34+ cells), freshly isolated CB-CD34+ cells and a cytokine cocktail. The test subjects were mice with streptozotocin-induced diabetes. Wounds treated with fresh CB-CD34+ cells showed more rapid repair than mice given the PBS control. Injection of expanded CB-CD34+ cells improved wound closure significantly, whereas the injection of the cytokine cocktail alone did not improve wound repair. The results also demonstrated a significant decrease in epithelial gaps and advanced re-epithelialization over the wound bed area after treatment with either expanded CB-CD34+ cells or freshly isolated cells compared with the control. In addition, treatments with both CB-CD34+ cells and the cytokine cocktail were shown to promote recruitment of CD31+-endothelial cells in the wounds. Both the CB-CD34+ cell population and the cytokine treatments also enhanced the recruitment of CD68-positive cells in the early stages (day 3) of treatment compared with PBS control, although the degree of this enhancement was found to decline in the later stages (day 9). These results demonstrated that expanded CB-CD34+ cells or freshly isolated CB-CD34+ cells could accelerate wound repair by increasing the recruitment of macrophages and capillaries and the reepithelialization over the wound bed area. Our data suggest an effective role in wound closure for both ex vivo expanded CB-CD34+ cells and freshly isolated cells, and these may serve as therapeutic options for wound treatment for diabetic patients. Wound closure acceleration by expanded CB-CD34+ cells also breaks the insufficient quantity obstacle of stem cells per unit of cord blood and other stem cell sources, which indicates a broader potential for autologous transplantation.


2018 ◽  
Vol 115 (37) ◽  
pp. 9080-9085 ◽  
Author(s):  
Jessica A. Carr ◽  
Marianne Aellen ◽  
Daniel Franke ◽  
Peter T. C. So ◽  
Oliver T. Bruns ◽  
...  

Recent technology developments have expanded the wavelength window for biological fluorescence imaging into the shortwave infrared. We show here a mechanistic understanding of how drastic changes in fluorescence imaging contrast can arise from slight changes of imaging wavelength in the shortwave infrared. We demonstrate, in 3D tissue phantoms and in vivo in mice, that light absorption by water within biological tissue increases image contrast due to attenuation of background and highly scattered light. Wavelengths of strong tissue absorption have conventionally been avoided in fluorescence imaging to maximize photon penetration depth and photon collection, yet we demonstrate that imaging at the peak absorbance of water (near 1,450 nm) results in the highest image contrast in the shortwave infrared. Furthermore, we show, through microscopy of highly labeled ex vivo biological tissue, that the contrast improvement from water absorption enables resolution of deeper structures, resulting in a higher imaging penetration depth. We then illustrate these findings in a theoretical model. Our results suggest that the wavelength-dependent absorptivity of water is the dominant optical property contributing to image contrast, and is therefore crucial for determining the optimal imaging window in the infrared.


Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 766 ◽  
Author(s):  
James Beeley ◽  
Gianluca Melino ◽  
Mohammed Al-Rawahani ◽  
Mihnea Turcanu ◽  
Fraser Stewart ◽  
...  

The authors have developed a wireless fluorescence imaging capsule endoscope, potentially capable of detecting early signs of disease in the human intestine which can be missed by white-light imaging (WLI) capsule endoscopy (Figure 1). Intestinal fluorescence imaging exploits variations in tissue autofluorescence between healthy and diseased areas in response to illumination, or application of fluorescent labels which preferentially bind to diseased sites. To validate the capsule’s capability to image fluorescently-labelled tissue, a small area of a sample of ex vivo porcine small intestine was sonicated with 6 nm CdZnMg fluorescent quantum dots, and the labelled area clearly differentiated from surrounding tissue by the fluorescence imaging capsule.


2020 ◽  
Vol 21 (19) ◽  
pp. 7104
Author(s):  
Moritz Alexander Birkelbach ◽  
Ralf Smeets ◽  
Imke Fiedler ◽  
Lan Kluwe ◽  
Martin Wehner ◽  
...  

For the post-surgical treatment of oral wounds and mucosal defects beyond a certain size, the gold standard is still an autologous skin or mucosal graft in combination with complex suturing techniques. A variety of techniques and biomaterials has been developed for sutureless wound closure including different tissue glues or collagen patches. However, no wound covering that enables for sutureless fixation has yet been introduced. Thus, a new system was developed that allows for sutureless wound covering including a transparent collagen membrane, which can be attached to the mucosa using a specially modified 2λ laser beam with integrated temperature sensors and serum albumin as bio-adhesive. The sutureless wound closure system was tested for its applicability and its cytocompatibility by an established in vitro model in the present study. The feasibility of the laser system was tested ex vivo on a porcine palate. The in vitro cytocompatibility tests excluded the potential release of toxic substances from the laser-irradiated collagen membrane and the bio-adhesive. The results of the ex vivo feasibility study using a porcine palate revealed satisfactory mean tensile strength of 1.2–1.5 N for the bonding of the membrane to the tissue fixed with laser of 980 nm. The results suggest that our newly developed laser-assisted wound closure system is a feasible approach and could be a first step on the way towards a laser based sutureless clinical application in tissue repair and oral surgery.


2019 ◽  
Vol 13 (2) ◽  
pp. 74-81
Author(s):  
Norihito Soga ◽  
Akihito Inoko ◽  
Jun Furusawa ◽  
Yuji Ogura

Introduction: Near-infrared fluorescence imaging with indocyanine green is a useful tool during partial nephrectomy. Because an accurate method for judging hasn't been established yet, the success rate may be slightly different and inconsistent. Materials and Methods: A total of 21 cases with suspected renal cancers who had undergone a partial nephrectomy were enrolled. We examined differences in the success rate between malignant lesions and the parenchyma by quantifying fluorescence in the pre-resection and ex vivo phases. Results: Pre-resection imaging showed a significant degradation of fluorescence in the focused lesion in 76.2% (16/21) of cases. A significant degradation was observed in 73.7% (14/19) of the total malignant lesions, 70.5% (12/17) of cases with a clear cell lesion, 100% (2/2) of cases with non-clear cell lesions, and 100% (2/2) of benign angiomyolipomas. In contrast, imaging of the ex vivo resected specimens showed a significant degradation in fluorescence of the focused lesions in 85.7% (18/21) of cases. A significantly degradation was observed in 84.2% (16/19) of the total malignant lesions, 82.3% (14/17) of cases with a clear cell lesion, 100% (2/2) of cases with non-clear cell lesions, and 100% (2/2) of benign angiomyolipomas. Conclusion: We firstly evaluated the efficacy of quantitative indocyanine green-based fluorescence as an objective method.


2009 ◽  
Vol 02 (04) ◽  
pp. 407-422 ◽  
Author(s):  
RALPH S. DACOSTA ◽  
YING TANG ◽  
TUULA KALLIOMAKI ◽  
RAYMOND M. REILLY ◽  
ROBERT WEERSINK ◽  
...  

Background and Aims: Accurate endoscopic detection of premalignant lesions and early cancers in the colon is essential for cure, since prognosis is closely related to lesion size and stage. Although it has great clinical potential, autofluorescence endoscopy has limited tumor-to-normal tissue image contrast for detecting small preneoplastic lesions. We have developed a molecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate which targets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescence-based endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T) subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivo whole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology. Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours post injection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstrated that modification of CC49 antibodies did not alter their specific tumor-localizing properties, and was antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probe targeting a tumor-associated mucin detects colonic tumors at the molecular level in real time, and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.


2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Matteo Tozzi ◽  
Luigi Boni ◽  
Gabriele Soldini ◽  
Marco Franchin ◽  
Gabriele Piffaretti

Intraoperative fluorescent imaging using indocyanine green enables vascular surgeons to confirm the location and states of the reconstructed vessels during surgery. Complex renal artery aneurysm repair involving second order branch vessels has been performed with different techniques. We present a case of ex vivo repair and autotransplantation combining the advantages of minimally invasive surgery and indocyanine green enhanced fluorescence imaging to facilitate vascular anatomy recognition and visualization of organ reperfusion.


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